This competing renewal application requests continued support for a pediatric cardiopulmonary research training program that has been active for almost 30 years. The training program described in this application has been substantially redesigned and enhanced in the following ways: 1) A new Program Director, Arnold Strauss, MD, has assumed responsibility for leadership and direction of the training program; 2) In addition to recruitment of trainees from a single Pediatric Division (Neonatology) as in the past, we propose that qualified postdoctoral trainees will be actively recruited from the Divisions of Pediatric Pulmonary Medicine, Pediatric Cardiology, Pediatric Critical Care and other divisions in the Department of Pediatrics; 3) Selected trainees will be encouraged to enroll in formal degree-granting programs leading to a Master of Science degree in either Public Health or Clinical Investigation; 4) Expansion of the research focus to include cardiopulmonary development and diseases; 5) Expansion of the mentor pool beyond the Department of Pediatrics to include proven basic and clinical research mentors in the Departments of Medicine, Pharmacology, Anesthesiology, Cell/Developmental Biology, as well as established multidisciplinary research centers of excellence in Human Genetics, Pharmacogenomics and the Health Services Research Center; 6) Explicit incorporation of a trainee mentoring program; 7) Renewed efforts to recruit underrepresented minorities into the training program via personal contact and via the new formal broad-based alliance between Vanderbilt and Meharry Medical College; and 8) A closer partnership between this pediatric cardiopulmonary training program and the adult-oriented pulmonary training program in the Vanderbilt Center for Lung Research which is substantially housed in the Division of Allergy, Pulmonary and Critical Care in the Department of Medicine. The overall objective of this training program is to produce much-needed investigators and leaders in basic and clinical research relevant to pediatric cardiopulmonary development and diseases.